our little one (3) just started skiing- and like her big sister (now 8 and proficient on "easier" black runs) she's using "edgie-wedgies", the contraption that lock the tips of her skis together. She learned how to position her feet before she ever got on skis: feet apart - slow, feet together - fast , and by her second day on the slopes she was making turns.
Personally, I don't like all the other "aids" very much; leashes, H-bars etc. seem to give the kids a false sense of security while encouraging bad posture. I'm not saying they never work, but there's so many kids out there who are literally just hanging in..